bget
We can query PDF of the manuscript via using Endnote or sci-hub. However, you can not easily get the supplementary files of scientific papers based on the two ways.

Here, we are developing and sharing an open-source tool bget to query supplementary files of scientific papers. The journals with high impact factors or those integrative publishers are a higher priority in our development plan: https://github.com/openbiox/bget/blob/master/doc/doi.md
It is noted that we do not want to distribute any pirated resources or cause unnecessary network congestion.
We hope this tool can provide an optional method to more easily query related files of scientific papers. Please use it in a non-invasive way (i.e. high concurrency, long continuous request).
Getting Started
# download bget on MAC OSX
# wget -c https://github.com/openbiox/bget/releases/download/v0.1.3/bget_osx
# mv bget_osx bget
# chmod a+x bget
#
# download bget on Linux
# wget -c https://github.com/openbiox/bget/releases/download/v0.1.3/bget_linux64
# mv bget_linux64 bget
# chmod a+x bget
#
# download bget on Windows
# wget -c https://github.com/openbiox/bget/releases/download/v0.1.3/bget.exe
#
# download nature.com files
./bget doi 10.1038/s41591-019-0627-8 10.1038/s41422-019-0228-6 10.1186/s40168-019-0760-0 -t 5 --suppl
# download www.sciencedirect.com files
./bget doi 10.1016/j.stem.2019.09.008 10.1016/j.cmet.2019.10.007 -t 5 --suppl
# If you do not at the subscribed IP, you need add this:
# --proxy http://username:password@host:port
Other usage videos: